(Plantaginaceae – the plantain family. Formerly included in Scrophulariaceae)

common name: Beard-tongue

Penstemonbeard-tonguecomes from the Greek πεντε (pente), five, and στημων (stémon), a thread (stamen). There is considerable confusion and controversy about the spelling of the genus name. Native Americans had long used the root of the plant to relieve toothache. The American geographer and botanist John Mitchell (1711–1768) published the first scientific description in 1748; although he named the plant merely as Penstemon, it was, in fact, what we now know as Penstemon laevigatus. Linnaeus then included it in his 1753 publication as Chelone pentstemon, altering the spelling to fit the notion that the name referred to the unusual fifth stamen. Mitchell’s work was reprinted in 1769, continuing with his original spelling, and this was ultimately accepted as the official form. Linnaeus’s spelling of the word, however, still persists, both among gardeners and among some botanists.

There are some 250 species of Penstemon. Most are native to the west of North America, ranging from Canada into Mexico, and some are east Asian. Some grow on the highest mountains, some in the desert, others in forest glades, in the foothills, or on plains. Some have woody stems, while others are herbaceous. Most species have narrowish pointed leaves; those in the basal clumps are larger, and those on the flower stems are smaller. The flowers are usually in bright reds or blues, but also in shades from soft pink through salmon and peach to deep rose, lilac, dark purple, white, and occasionally yellow.

The most distinctive feature of the genus is the prominent staminode, an infertile stamen. This staminode takes a variety of forms in the different species; while typically there is a long straight filament extending to the mouth of the corolla, some are longer and very hairy, giving the general appearance of an open mouth with a fuzzy tongue protruding – hence the common name.

Most penstemons are herbaceous perennials, the remainder being shrubs or subshrubs. They range in height from 10 cm to as much as 3 metres.

Although these are among the most attractive native flowers of North America, they have been more actively cultivated in Europe, and hundreds of hybrids have been developed there since the early 19th century. A number of different species have been used in the hybridization progress, notably Penstemon cobaeus and Penstemon hartwegii. There are also many cultivars.

The foxglove-like flowers appear mainly in summer, borne at the end of erect flower spikes; they are slightly hanging and tubular to bell-shaped, with 2 upper lobes and 3 larger lower lobes.

Native North Americans, as well as using the plant for relieving toothache, as mentioned earlier, also used the woody roots as a painkiller, and as a means to stop bleeding.

Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.